Abstract
The
Arabidopsis
mutation,
los2
, impairs cold-responsive gene transcription, acquired freezing tolerance and plant resistance to chilling under certain conditions.
LOS2
was isolated through positional cloning and shown to encode an enolase in the glycolytic pathway. In animal cells, enolase has also been known to function as a transcription factor that represses the expression of c-
myc
by binding to the c-
myc
gene promoter. LOS2 fused to green fluorescent protein is targeted to the nucleus as well as to the cytoplasm. LOS2/enolase protein can bind to the
cis
-element of the human c-
myc
gene promoter and to the gene promoter of STZ/ZAT10, a zinc finger transcriptional repressor from
Arabidopsis
.
STZ/ZAT10
expression is induced rapidly and transiently by cold in the wild type, and this induction is stronger and more sustained in the
los2
mutant. Furthermore, the expression of a
RD29A-LUC
reporter gene is repressed significantly by STZ/ZAT10 in transient expression assays in
Arabidopsis
leaves. Our results demonstrate that cold-responsive gene transcription in plants is controlled by a bi-functional enolase.